Improvement in steam engine



I N.PETERS. FHDTO LTHOGRAPH WASHINGYON D C JOHN n. MILLS, or noSToN, MASSACHUSETTS.

Letters Patent No. 62,556, dated .Marca 5, 1867.v

.i IMPROVEMENT IN STEAM ENGINE.

@te tlgehnle nient tu la tti-rse @sitas @anni unt -limiting putt af tige smut.

T0 ALL TO WHUM THESE PRESENTS SHALL COME:

Be it knownthat I, JOHN H. MILLS, of Boston, in the county of Suffolk, and State of Massachusetts, have invented certain new and `useful improvements in portable Steam Engines; and I do hereby declare thel following to be a full, clear, and exact description thereof', reference beinghad to the accompanying drawings, and in which Figure 1 is a side view; and

Figure@ is a frpnt end view; and

Figure 3 is a vertical'and transverse Section .of a portable steam engine, constructed in accordance with my invention. i i

Figure 4 is a horizontal section otone ofthe sectional boilers, to be hereinafter described.

The object of this invention is to produce a portable steam engine, simple, compact, and cheap in its construction, efficient in its operation, and one which can be separated and' packed in parts for convenience of transportation.

My invention consists inV constructing a portable engine having two oscillating cylinders of diierent capacities, the exhaust steam from the smaller cylinder being carried by a connecting pipe into the larger, in which it is used expansively. The invention also consists inthe application to or combination with portable engines of a series of sectional .castiron boilers, in such manner as to increase or diminish at pleasure the amount of steam-converting surface of tho combined boilers, as well as to enable the whole engine to bel packed in separate portions for transportation in localities where large bodiesA cannot be conveniently carried. The invention further consists in .carrying the connecting pipe of the two cylinders over the tire, or through the tire-chamber of the same, in order to superheat the exhaust steam passing from the smaller cylinder, as well as to vaporize and utilize the condense water, which would otherwise be carried away in the final exhaust from the larger cylinder. By this means thc pressure of steamibetween the two cylinders is considerably increased, and the consumption of fuel economiz ed. The invention further consists in the peculiar construction or arrangement of the steam-communicating passages of the steam chests and cylinders, and their' connection with the trun'nions of the said cylinders, in manner andhfor the purpose as hereinafter referred te and described.

By referring to the above-mentioned drawings, as constituting part of this speciiication, it will be seen that the bed-piece or foundation ofthe engine is shown at A as recessed or rebated, as Shown at a4, for the reception and support of a Series of cast-iron sectional boilers or generators, B B, ctc., properly bolted together, the bed being of suiicient size to contain any number of these sectional boilers which the engine will ever require; the number of them ortheir combined capacity, a's shown at B in the accompanying drawings, being the amount which the engine, as therein exhibited, `will probably require, the connections of the cylinders and the working Shafts being accommodated to this number. Should more be required, however, they may be added in any number desired 'without removing or changingthese connections. The smaller cylinder is shown at C, and

the larger at D, they both being constructed with horizontal trunnions E E', supported in boxes, a3 a3, formed upon brackets, F F, securely bolted to opposite sides of the combined boiler B', and so that the cylinders Shall oscillate freely upon the said trunnions, the outer one, E, of which is solid or homogeneous with the cylinder, while the inner one, E', is hollow, or formed with steam passages, as hereinafter described. The steam chest Gr surJ mounts the cylinder in the usual manner, its valve or valves being operated in any manner well known tn mechanics.

By referring to iig. 3 of the drawings it will be seen that the sectional boilers B are composed of a closed steam and water pipe or reservoir, H, made in' the form of a right-angular yoke, with its side branches, a a, resting within the rebate a4 of the bedA of the engine, which also has a central space, I, formed in it to serve as an ash-pit. Extending across between the-lower parts of the branches a a of the generator H is a grate, J, for supporting the fuel of the lire-pot K.' The outer surface of the pipe H is formed with oisets or lips, 6 b, for the purpose of making a tightjoint with the next adjacent boiler, and also to form a hot-air chamber, L, within thc yoke of the said pipe. The side portion a a of this pipe H communicates with thetop horizontal portion by means of curved or bent pipes c c t', etc., the central one, e', of which being of larger areathan the others, and coming in direct contact with the. heat of Jthe fire in the reopot K. The pipes H H, etc., communicate sse 2 with each other by means of ports or pipes d d d di, the upper ones, d d, being steam-communicating ports, and the lower ones, d' d', being water-communicating passages. By the peculiar 'construction and arrangement of the pipe H, in connection with the pipes c c c, ctc., the water has a free circulation from the lower part of the boiler upwards, the large central pipe or space enabling the water to pass directly up the centre, and then outwardly and down throughthc side branches a a of the pipe H, a portion of it'falling to the bottom thereof, and a portion again raising throughthc pipes c c c. The trunnion E', before, referred to as being hollow, has two' passages, ef, formed within it, the steam from the boilers being conducted by means oi'ia' pipe g, (lcadingthrough the box a3 supporting the trunnioin) into the passage @from whence it passes through the steam chest G into the cylinder, and after having performed its office therein, escapes through the usual port and exhausts into' the passagefof the trunnion, from whence it enters the connecting pipe h, connecting the trunnion E ofthe cylinder C with that ofthe cylinder D,`it being understood that communicationl between the two passages c andf is cut ofi, or as shown by the partition e in iig. 3 of the drawings. By this arrangement of steam passages in the trunnion, I am enabled to employ one trunnion only for this purpose, leaving the opposite trunnionsolid, thus rendering it much stronger, and not liable to heat. Furthermore, avertical passaggfl, is made in the trunnion E leading downward through the bracket F, and is supplied with a stop-cock, fl, as represented. When exhausting from the cylinder C to the cylinderD this cock should be closed. When the cylinder C is used alone, and the cock of the connecting pipe shut, the above-n1entioned cock f2 is to be opened, which lwill allow the exhaust from the cylinder to pass into the atmosphere through the passage f1. Thejoint connecting the communicating pipe 7L with the trunnion should be properly packed, to prevent leakage, and the pipe is to be carried through the air-heating chamber L and between the series of steam pipes c c c of each boiler, B B. By this means the steam within the said pipe h is superheated to an extent togreatly increase its pressure, the gain increasing in proportion to the pressure of the steam as it leaves the rst cylinder. Another advantage gained by the passing the pipe through the nre-chamber, in addition to utilizing the surplus heat of the lrire, is the fact before mentioned, that any condense water within it will be vaporized or convertedA into steam, thus materially increasing its volume, and consequently lesseniug the amount of fuel required to run the engine. It will be understood that the steam enters and leaves the cylinder Dand its trunnion E in the same manner as in the cylinder C; As each cylinder is supplied with steam directly from the boiler 'by an independent pipe, and the connecting pipe 7L being provided with a stop-cock at any convenient point between the two cylinders, it will be evident that either cylinder may be used independently, and thus form an engine in itself; or, when great power is required, the two may be used together, with the steam leading directly into them, by which means much more powerwill be obtained from the two than whenexhausting from one to another.

I amaware that thc principle of exhausting steam from one cylinder to another oi' a steam engine is not new and forms no part of my invention, and conscquently lay no claim broadly to this principle.

What I claim as my invention, and desire to secure by Letters Patent of the United States, is as follows:

1. The combination, with a series of sectional boilers, of the steam cylinders under the arrangement herein described, so that either cylinder alone, or both together, may be used with the full power of steam Agenerated bythe said boilers, or so that the smaller cylinder shall exhaust into the larger, substantially as set forth.

2. The pipe for connecting the two cylinders, arranged so as to pass through the combustion-chamber or fire-pot of the boilers, substantially as shown and specified.

3. The-arrangement of the boiler B, consisting of the bent pipe H and connecting 4pipes c, operatingtogether as Shown and described. i

4. The arrangement of the inner trunnions of the steam cylinders in such manner that the steam may pass directly from one cylinder to the other through the said trunnions, as and for the-purposes set forth.

JOHN H. MLLS.

Witnesses:

C. W. BALDWIN, FREDERICK CURTIS. 

